1. Field of the Invention
The present invention relates to a protective film separator in a semiconductor wafer grinding process, and more particularly, to a separator for removing a protective film affixed to an electric circuit patterned side of a wafer to protect the wafer in a semiconductor wafer grinding process.
2. Description of Related Art
After completing an electric circuit patterning process to a side of a wafer in a semiconductor process, the other side of the wafer is generally ground in a wafer grinding process.
The wafer grinding process polishes the backside of a wafer and removes a polysilicon layer or an oxide layer that is adhered to the backside of the wafer while the semiconductor process is performed. In addition, the wafer grinding process abrades the backside of a wafer making a thinner wafer, which results in simultaneous improvement in both electric and heat conductivity of a semiconductor device.
Because such a wafer grinding process generates many impurities, a wafer protective film is adhered to the patterned side of a wafer so that the impurities do not cause damage to the electric circuit patterned side of the wafer.
The adhered protective film is removed after completing the wafer grinding process by a protective film separator. Conventionally, two types of protective film separators have generally been used.
The first type of protective film separator attaches an extra removing tape to the adhered protective film and simultaneously irradiates ultraviolet rays to weaken an adhesive strength of the adhered protective film. Then, a roller presses the wafer surface and rotates continuously on the wafer surface to remove the adhered protective film with the extra removing tape.
The second type of protective film separator applies a piece of a heat-activated adhesive tape to a protective film adhered to a wafer surface, and applies heat from a heater to the heat-activated adhesive tape for a few seconds so that the heat-activated adhesive tape adheres to the protective film. Thereafter, the second type of protective film separator irradiates ultraviolet rays to weaken an adhesive strength of the protective film adhered to the wafer, and a tape-removing robot finally removes the protective film with the heat-activated adhesive tape.
The two conventional types of protective film separators continuously consume extra tape, i.e. the extra removing tape and the heat-activated adhesive tape, which causes a continuous increase in the expense of raw materials.
Additionally, either the roller or the heater for removing the protective film presses against the wafer thereby generating severe stress on the wafer surface. Moreover, impurities or residue stained in the protective film can cause damage to the patterned wafer by virtue of the physical contact, which further adversely affects the final wafer yields.
To overcome the above described problems, a feature of a preferred embodiment of the present invention provides a protective film separator for removing a protective film, wherein the protective film separator removes the protective film in a semiconductor wafer backside grinding process, thereby eliminating the need for extra removing tape or heat-activated adhesive tape so that the cost of raw materials may be reduced.
Another feature of an embodiment of the present invention provides a protective film separator that reduces an external force applied to a wafer, thereby preventing a patterned side of the wafer from obtaining impurities while the protective film is removed.
In order to achieve the above feaures, preferred embodiments of the present invention provide a protective film separator comprising an adsorption means and a peeling means. The adsorption means applys a vacuum to a part of a protective film adhered to an electric circuit patterened side of a wafer, and separates the part of the protective film from the patterned side of the wafer. The peeling means presses each side of a part of the protective film that has been separated from the wafer by the adsorption means and separates unpeeled parts of the protective film from the patterned side of the wafer.
The peeling means includes a body, top-peeling rods installed in a side of the body, and a bottom-peeling rod. The bottom-peeling rod vertically penetrates the body, moves vertically through the body, and confronts the top-peeling rods in a predetermined interval.
In addition, the top-peeling rods include two top-peeling rods placed apart from each other in a predetermined interval so that the adsorption means is located between a first top-peeling rod and a second top-peeling rod.
The adsorption means includes an adsorption plate in a semi-lunar shape to adhere closely to a rounded edge area of the wafer. The adsorption means also rotates a predetermined angle after adhering to the protective film.
These and other features and aspects of the present invention will be readily apparent to those of ordinary skill in the art upon review of the detailed description that follows.xe2x80x9d at the end of the Summary of the Invention.